Does Subsonic 3 ActiveRecord Handle Many To Many Relationships

Everything uses the Repo - it's at the core of all the templates and is now in SubSonic's core code. I can't help you in choosing, necessarily, but what I can say is that ActiveRecord will allow you the most options.

One thing I haven't shared with people (that I will soon) is the built-in testing for ActiveRecord. In your test project, just use "Test" as your connection string and the AR template will not hit your DB. Moreover you can use the static "Setup" method to pump test records into the in-memory list.

Adds/Updates/Deletes all work agains the in-memory stuff.

In terms of "Heavy" - I like to think "Easy" trumps. And it doesn't get any easier than ActiveRecord.

You can still use SubSonic 3 as a DAL and let SubSonic 2.2 generate the migrations for you. You just need sonic.exe and it's dependencies to execute the migration files.

To be more precise, I have folder Migrations in my DataLayer Project, that keeps all the migration Files but set the BuildAction to none. So I have Syntax Highlighting (but no error checking unless I set BuildAction back to compile) but the code does not mess my project.

You can keep them in an own project, of course. But I like it this way to have it under version control and be sure that my current DAL is matching my migration version.

In addition, I have named my config file migration.config (instead of app.config/web.config) and use this commandline to execute my migrations.

Command:           /path/to/sonic.exe  
Arguments:         migrate /config migration.config
Working Directory: $(SolutionDir)MyProject.Datalayer

Notice the /config switch to override the config file sonic.exe is looking for.